I tried a PID controller with a slow cooker and it works fine, but, if you don't want to spend a lot, there are simpler alternatives. The first one that worked well was an electric frying pan with a dial control. I was able to set the dial to maintain a fairly accurate temperature at 55 and 75 centigrade. For a larger volume cooker I picked up a used electric turkey or roasting pan made by Rival, it cost $15 at Goodwill and it worked fine. I use a Taylor thermometer, the thermocouple wire is thin enough to allow the lid to close, I probably could insert the probe through the lid with very little trouble. I would also put a small fish tank pump into the larger pot to provide circulation. I have not tried the final method, but, I think it should work and that is to put a dimmer switch between the power source and the slow cooker to regulate the heat, if it works, it would be much cheaper than a PID controller, just a thought, somebody with better electrical knowledge might comment.

I have a PID controller, crock pot but I find for most things a really nice thick ice chest is fine. Got mine off Ebay and it's really a super insulated shipping container, the walls are 3 inches thick. That chest loses 1 degree F, an hour.

It helps to "preheat" the meat. I use a large pot of water on the stove to heat the water for the ice chest, I heat it a few degrees higher, and fill the chest. Let that stablise. Meanwhile reheat a pot full of water to your desired temp, toss in the meat and remove the whole thing from the heat.

Wait 20 minutes and toss the meat into the ice chest. Now you'll have a much smaller heat loss to content with.

Calibrate your ice chest, use the same volume of water and figure out how much boiling water do i need to add to raise the temp 1 degree, or ice to drop it 1 degree.

A large thick ice chest gives you a very stable water bath, and as long as you check the temp every 20 mins or so and adjust, works very well.

I have a Fisher Paykel convection oven and the lowest temp is 80 degF. Haven't tested how well it holds that temperature and how much it deviates. Interesting...I never considered using my oven as a sous vide device.

I put three mason jar rings in an electric fry pan, and then I put a Dutch Oven filled with water on top of them. I pour water or oil into the electric fry pan, and set the fry pan for the temperature I need. I check the temp with thermometers in both the fry pan oil/water, and in the Dutch oven. Once stabilized, the water temp in the Dutch oven seems to track really well, especially if using oil in the fry pan.

A Pork Loin Roast using this setup was absolutely delicious, as were some chicken breasts - not dry at all - and in both cases, the collected juices made fantastic gravies.

I am about to take the sous vide plunge. I was wondering if anyone has any experience or thoughts on using one of these 10.5 quart soup warmers for your heated water bath. They seem to be pretty generic and marketed by lots of people. The reason I am considering one is because the 10.5 quarts would provide more volume than your average crock pot, for example. I was thinking this might be a plus if I had a large roast or something. Thanks for any ideas or feedback!

I find recipes for cooking rib roasts or leg of lamb in the "largest size bag". The bag to which they refer mush be larger that the Foodsaver bags. Who makes the roast size bags suitable for sous vide ad where can they be purchased? I am not seeing anything online.

I've tried PID controllers with my 7-quart oval CrockPot but a Johnson Controls A419 thermostat has proven to be more practical in this area. We get very brief power interruptions about once a month lasting for perhaps a quarter second that will reset a PID controller to inoperative states. The thermostat sails through these and power interruptions lasting much longer. It's no fun coming home to a ruined meal when the PID controller resets.

I use an aquarium airstone for circulation. I have found it quite effective. Although the thermostat produces some temperature cycling plus or minus a degree or so, inside the bag the meat core temperature is rock steady. Big roasts reach final temperature faster with circulation than they will with the name-brand uncirculated cooker. This means that I can cook roasts up to five lbs. with confidence in my 7-quart crock pot while the 12-quart name brand cooker requires this sized roast to be cut up into small portions to be cooked.

I have the experience of over 1000 suppers (6000 servings) over four years with this setup. The meat is seasoned and bagged then refrigerated overnight and goes into the water bath in the morning before I leave for work (sometimes a marinade is poured off). It's a simple and quick task of quick-searing on my backyard gas grill in the evening -- taking about three minutes of cooking time.

I have always used Ziplock freezer bags rather than a vacuum sealer.

The results are splendid, the same perfect results as with a PolyScience circulator. 3-4 lb tri-tips are miraculous this way. Pork loins are sensational, chicken breasts have flavor never accomplished other ways.

I have one of the new WiFi Nomiku circulators on order -- which I plan to use with a 28-qt ice chest for making Thanksgiving feasts.